In recent years, an increase in age-related diseases such as osteoporosis, dementia and the like has become a serious social issue along with aging of population. Various drugs have been developed to prevent or improve such age-related diseases. However, since drugs always need to take side effects into consideration, in recent years, attempts have been made to prevent or improve age-related diseases through a change in eating habits or intake of a specific food ingredient. For example, it is known that osteoporosis is prevented or improved by intake of a basic protein contained in cow milk (see Patent Document 1). A dementia therapeutic agent that prevents or improves Alzheimer-type dementia and contains sphingomyelin which is one of the phospholipids containing relatively abundantly in cow milk as an active ingredient has also been known (see Patent Document 2).
Deterioration in peripheral sensation can be known as one of the age-related symptoms. The deterioration in peripheral sensation also occurs due to not only aging, but also diseases such as diabetes and the like. Deterioration in peripheral sensation may occur following troubles; for example, as it can't feel hot immediately when touching a hot object, a risk of burns or the like increases or the discovery of an injury becomes delay due to deterioration in pain sensation. In recent year, in order to decrease such a risk, studies that improve deterioration in peripheral sensation due to ageing or diseases have been conducted. For example, it has been reported that sphingomyelinase or phosphatidylcholine-specific phospholipase C, which are enzymes that increase biosynthesis of endogenous ceramides promote differentiation of PC-12 cells which is one of the neural cell lines through the secretion of neurotrophic factors from Swiss 3T3 fibroblast cells (see Non-patent Document 1). However, since ceramides and the above enzymes are not food ingredients, it is necessary to take account of safety. Therefore, a safe agent that is effective to improve deterioration in peripheral sensation through daily intake or skin application has been desired.